1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a micro Ball Grid Array (.mu.BGA) semiconductor device.
This application is a counterpart application of Japanese application Serial Number 117442/1999, filed Apr. 26, 1999, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
FIG. 1 is a cross-sectional view of a conventional .mu.BGA semiconductor device. The conventional .mu.BGA semiconductor device 1300 is made up of a semiconductor chip 1301, conductive layers or strips 1310 and a tape 1308. An integrated circuit having a plurality of external terminals 1304 is formed on a front or top surface of the semiconductor chip 1301. The tape 1308 includes insulating layers 1309, 1313 with the conductive layers which are sandwiched between the insulating layers 1309, 1313. For example, the conductive layer 1310 is made of copper (Cu). The insulating layer 1309 is made of polyimide or glass epoxy, while the insulating layer 1313 is made of solder resist.
A passivation layer 1305 covers the front surface of the semiconductor chip 1301. Each of the conductive layers 1310 is electrically connected to one of the plurality of external terminals 1304 and is exposed from an opening portion (hereinafter referred to as an "opening") 1303a. The tape 1308 is fixed to the passivation layer 1305 via a buffer layer 1307. The connection portions of the conductive layers 1310 to the external terminals 1304 are covered by a resin 1302.
The conventional .mu.BGA semiconductor device, however, can not be stacked and mounted on the board, since the exposed regions of the conductive layers 1310 from the openings 1303a, which are used for electrical connection with the other external device such as a semiconductor device, are formed only on the front side of the semiconductor chip 1301.